There are a number of videos on You Tube to search & View.
None are Corvette specific but most still applicable.
"5 things you should never do in a dual clutch transmission vehicle”

In a DCT the odd numbered clutch is engaged in 1st gear when you
stop and the car will creep if you take your foot off the brake.

 

Not in every DCT equipped car. I have no Idea on the C8 as i don't have one yet.

I do have a DCT in my Alfa 4C and it doesn't creep or engage when your foot isn't on the accelerator (gas) pedal. I can sit at a light in "1st" gear and not move with no pedal press. Also The parking spots at my job are on a slight incline. When reversing into a spot, If stop backing up and not use the brake. It will roll down forward.

 

Understanding the difference between the Tremec DCT and a "slushbox" automatic will help explain some of the issues folks have expressed! It's NOT a "slushbox" (thank goodness or I'd be driving something else!) It does NOT have a fluid coupling torque converter that can provide smooth power from 0 speed and allow the car to creep forward say in stop-and-go traffic by modulating the brake pedal. Some have complained about the DCT NOT operating like their "slushbox!"

SIDEBAR
Think of the DCT as two standard shift transmissions (which it is. ) Each with it's own clutch. When you slow down, unlike a standard shift where you would disengage the clutch, the Tremec DCT 1st gear clutch does NOT disengage. It slips as some folks do with a standard shift when on an incline to keep it from rolling back (not good practice but can be done.) Not a problem with the C8 DCT as the clutch is bathed in transmission fluid that has a large liquid to liquid cooler. As the Chief Corvette Engineer said, it is not an excess wear issue, it's built to handle that slippage.

So as you slow down, at about ~3 mph the 1st gear clutch starts to slip, it has to so the engine doesn't stall. You can feel the slip (if you are preceptive.) So sure, you have to keep your foot on the brake or it will creep forward! Just as you must with a "slushbox" but the difference is with a "slushbox" there is no transition speed. The torque converter can transfer power smoothly from 0 mph.

Therefore in bumper-to-bumper traffic I would treat it more like a standard shift and let the car in front move a few car lengths then release the brake pedal so the clutch can fully engage and move forward. You can let it creep with the clutch slipping BUT you'll feel the difference. When I pull slowly into my garage, as the mirrors come close to the door edge, it does feel different than say the wife's BMW X5, which has a good "slushbox" (if that is possible.)

PS: Understand many folks are not gearheads and don't want to think thorough the mechanical differences but some of the "silent majority" who view Threads might appreciate this way of thinking about what's happening! Having only driven standard shifts for my DD in 60 years, getting used to the DCT was an issue. I drove in Manual Mode for a month AND when I came to a Stop Light pulled both shift paddles, which disengages BOTH clutches (the only way to disengage the clutches.) Then I released the downshift paddle when stopped and kept the upshift paddle depressed until ready to move forward. On a flat surface no need to keep my foot on the brake! BUT for the past 3 months drive a different way. I have Z MODE set with Power in Track, which provides a much more aggressive drive (as I was used to in my 2017 Grand Sport, etc.) I now am used to the slight slipping and don't bother with pulling both shift paddles to put them in neutral as I come to a stop. Most fun Vette of the 6 I have owned.

Just use the Tremec DCT to it's advantage and forget those old "don'ts" with DCT's as that is for older ones!

 

I predict a locked thread soon.

 

Only if people get nasty.

 

Why?

 

Is there a question here or a point you are trying to make?

 

Thread title is a fail.

You're talking about torque converter (TC) automatics vs. dual clutch automatics. They are both "automatic transmissions." There are also great manual-shifting TC automatics out there, such as the ZF8, and the Ford and GM jointly developed A10.

 

Driving an auto car (with a torque converter) and a car with a DCT is different.

For example they don't recommend you "creeping" foward a DCT car. Say if you're inching in stop and go traffic. Wait for a good gap, then slowly move foward.

I say the best of both worlds IS the ZF 8 speed auto. With the torque converter.

As fast, BOTH UP AND DOWNSHIFTS, as a DCT yet it is capable of handing a lot of power. The stock tune file it comes with on most cars, have been spot on, IE: the FCA products, BMW M cars like the M5, M340I, M8 etc

It's actually my absolute favorite auto. Yes even moreso than the porsche PDK. And since i don't have a porsche (wish i had a turbo s lol), then i say the ZF 8 speed is my favorite and have quite a good amount of experience with that trans.

It is incredible. But the DCT's in the C8's are just as good!

Can't wait to flick the paddles on my C8!!!

 

I have a 4C as well, in fact going to get her out of the garage now. Agree with what you say exactly, you do want your foot on the brake when stopped though.

 

Just another transmission opinion ... automatics with torque converters totally suck. I suppose someone has made a decent one, but the 2015 Z51 I had required a torque converter replacement due to chatter at 40mph-ish and replacement torque converter did the same thing, so replaced the car with a 2017 Z51 thinking that the design would have been fixed. Nope - same fricken issue with that car. GM refused torque converter replacement in favor of fluid change. That fixed the problem for about 3 months, then back to the same chatter issue. I sold the car (6th Corvette) swearing I would never get another one. I have ordered a 2021 C8 last July that I should get in March/April time frame, ONLY because they now have DCT. I'm confident there will be no further transmission issues.
BTW - I have a 2019 Ford Edge ST with an A8 - guess what ... transmission issues in shifting - multiple TSB's to fix the problem.

 

My BMW 335is did not roll forward at a light. ZF 7DCT. Butt not sensitive enough to find a difference between my Z4's ZF8 & the ZF 7DCT. Outside of the 3/4 M series which still offer the 6MT all the new M cars are ZF8 & no longer offer the 7DCT or 6MT as an alternative.

 

You've obviously never owned a vehicle with the outstanding German-built ZF8. It is bullet-proof and universally praised. It is well-known the GM A8 was problematic, and DCT's have sucked on occasion as well.

The ZF8 is used by Alfa-Romeo, Audi, BMW, FCA, Jaguar/Land Rover, and Mercedes-Benz among others. They are infinitely tunable depending upon whether the manufacturer is going for sporty vs. sedate, and most have controls for changing the shift characteristics.

I've owned cars with ZF8s tuned such they are almost indistinguishable from the excellent PDK, and BMW among others have dumped DCTs in favor of the ZF8.

 

You got that wrong.

The GM 8 SPEED used in the C7's (and the CTSV V3) SUCK. They are GARBAGE. TRASH. ****!

The ZF 8 speed is probably THE BEST auto you can get in a car right now. Because it does everything so well. That's why a lot of car makers adopted this trans to use in their cars.

 

You're right- completely different and the Tremec DCT has some neat features GM and Tremec were able to build into the trans for launch mode.

Here are some key features:This summary of the C8 Transmission operation includes comments from GM’s DCT Controls Manager and a C8 form post by Tadge. Pretty impressive options.

1. The C8 DCT transmission has different automatic shift strategies for the various drive modes, which adapt in real time. The more aggressive, the more spirited you drive, the more aggressive the car's responds, -start to relax, the car starts to relax.

2. The DCT uses latitudinal and longitudinal accelerometers, and looks at information like throttle position and steering angle to gauge how the car is being driven, and react accordingly. In Track mode set to automatic, the car will downshift aggressively when the driver is braking hard into a corner, and hold upshifts until corner exit.

3. The C8 has two manual modes. If you pull a paddle while in Drive, you get a temporary manual mode, which automatically times out, or can be exited sooner by holding the upshift paddle. In this mode, the car will automatically upshift at redline. If you press the M button in the center console, you get full manual mode. There's no time out, and the car won't upshift at redline.

4. Hold the downshift paddle, the DCT will serve up the lowest possible gear. Do that while braking, and the transmission will keep downshifting as engine speed allows.

5. Pulling both paddles at the same time is equivalent to pushing in the clutch pedal on a manual car, which allows you to rev the C8's new V-8 as much as you want.

6. The paddles are directly wired to the transmission control module (TCM) for quicker response times. This doesn't mean the paddles will give you a downshift that over-revs the engine—the TCM prevents that.

7. With the C8's Performance Launch mode, the car uses the inertia of the engine coming down between revs to propel the car forward.

8. You can avoid V4 mode using the “M” manual button or temporally for 5 seconds after pulling the last shift paddle. The new "Z" mode comes from the factory set up as an extra sporty mode including shift schedules pulled from the "Track" mode, so that will be V8 only. You can customize "Z" mode any way you want, so if you elect another shift pattern, V4 mode will return.

9. GM and Tremec have also said they found a way to have both clutches engaged (I assume for a fraction of a second) on fast acceleration (at least 1st and 2nd) They have not discussed the details. these are quotes: 1st by GM’s Chief Engineer, Piatek: “We found that during very aggressive launches we can drive torque through both shafts/clutches simultaneously which improves the 0 to 60 times.” 2nd from Road and Track: "With the C8's Performance Launch mode, the car will actually use the inertia of the engine coming down between revs to propel the car forward. Chevy calls these "Boosted Shifts," and they're only used with a Performance Launch."

MY C8 DCT EXPERIENCE;
Had talked to an old timer, who like myself had only driven standard shifts. But he has a new Ferrari and when I asked how often he used Manual Mode- he said always! I thought, yep I'll just use Manual Mode (and did for a month) until a poster showed what you can do in Z MODE with POWER set to Track! Found in Manual Mode on my daily leaving the Stop Sign at the end of my street to merge into ~70 mph traffic (sometimes heavy) on a 4 lane divided highway, turning the wheel put the upshift paddle out of reach. In Manual Mode the trans will not shift to 2nd by itself! You must pull the upshift paddle or it will hit the rev limiter and stay there until you shift! Not good as the 5.17:1 dif ratio combined with 1st gear is 14:1 and reaches redline at the blink of an eye. For comparison, my 2017 GS had a 10:1 torque multiplication in 1st gear and the C7 Z06 only 9:1. Then I discovered Z MODE with Power set to Track (all other controllable variables can be set wherever you'd like, i.e. brake boost, steering, ride and NPP) then the trans shifts to 2nd close to redline at WOT. Can still pull the shift paddles but it is driving about the way I drove my 2017 Grand Sport- seldom used more that 5th. Now Z-MODE the way I have it set, is similar!

It's essential a software issue but this is what you get. Watch the video at the end as this fellow drives just like I do!

Here is why I have my Z MODE set to Power in Track and at the end a video by a forum member poster showing how it's a different car WITH POWER SET TO TRACK:

• The car will upshift at much higher rpm than when in TOURING, SPORT or MY MODE.
• It will seldom shift past 5th gear (Note 4th and 5th are OD ratios, like 6th, 7th and 8th) providing engine torque with modest throttle increases WITHOUT downshifting.
• It will not go into V4 mode.
• When braking it will downshift at higher rpm and rev match makes it perfectly smooth in each gear.
• Note, you can still use the shift paddles. So if the software is keeping the car from going past 5th and you’re just cruising, pull the upshift paddle and you can shift to 6th or 7th. If making an aggrieve turn you can downshift at whatever rpm you'd like as you brake. But you'll probably find when in Z MODE with Power set to TRACK it will downshift at high enough rpm with aggressive braking. I do that when returning to my 25 mph speed limit street from ~70 on the highway. It goes thorough all gears like 6th to 5th to 4th to 3rd with hard braking faster than anyone could stir a stick or operate a clutch! Makes great “music” with perfect rev match in each downshift!

Good video describing what I said in words by a forum member: https://www.youtube.com/watch?v=RI9M...annel=jrock702

 

My Mercedes creeps when you take your foot off the brake (unless you engage hill hold)

 

The ZF8 is only as good as the company tuning it. There are reviews complaining about sluggish operation in the ZF8.

 

Yes, and I acknowledged that (sporty vs. sedate). But, ZF8 tuning is more a function of what type of vehicle the manufacturer puts it in to best suit that customer demographic. It's driver adjustable in most sporty cars, much like both the C8 Tremec DCT and Porsche PDK.

The ZF8s in my current Ram 1500 and prior Jeeps, are very different than the ones in my Jaguar F-Type and Alfa Giulia TI Sport, and those were tuning choices made by the manufacturer. However, all have been great for their application.

 

I just picked mine up and as I am a left foot breaker trans works great for me. I also have a SMG M3 and An Alpha auto. regarding the trans, I prefer the corvette. Really smooth around town. The SMG also works great as a left foot breaker car.

 

Damn awesome!!

You know a lot about the C8 man!!

I can't wait to flick the paddles on mine!!